In difficult-to-machine materials where mechanical machining to machine holes is difficult, machining is generally performed using an electrochemical machining method or an electrodischarge machining method. In particular, when machining holes in a difficult-to-machine material having a high aspect ratio, it is preferable to use the electrochemical machining method.
For example, in a turbine blade of a gas turbine, cooling holes are formed that circulate a coolant, which cools the turbine blade. In order to realize optimal design in terms of thermal and aerodynamic performance, that is, in order to efficiently cool parts that reach a high temperature, such as a blade profile part and a platform etc., it is preferable for a shape of the cooling hole to be curved along a geometrical shape of the turbine blade.
Here, Patent Document 1 discloses, for example, an electrochemical machining assembly that is capable of forming a curved hole in a workpiece using a curved electrode.